From a basic to a functional approach for developing a blood stage vaccine against Plasmodium vivax

ABSTRACT

Introduction: Numerous challenges have hampered developing an anti-malarial vaccine against the most widespread malarial parasite worldwide: Plasmodium vivax. Despite the progress achieved in studying proteins in short-term in vitro culture or in experimental models, there is still no clear method for defining which antigens or their regions should be prioritized for including them in a vaccine.

Areas covered: The methods used by research groups so far which have focused on the functional analysis of P. vivax blood stage antigens have been reviewed here. A logical strategy orientated toward resolving two of the most commonly occurring problems in designing vaccines against this species has thus been proposed (i.e. the search for candidates and evaluating/ascertaining their functional role in the invasion of such molecules).

Expert commentary: Advances in knowledge regarding P. vivax biology have been extremely slow. Only two key receptor–ligand interactions concerning merozoite entry to reticulocytes have been reported during the last 20 years: PvDBP1-DARC and PvRBP2b-CD71. Despite increasing knowledge about the parasite’s intimate preference for its host cells, it has yet to be determined which regions of the merozoite molecules characterized to date meet the requirement of inducing protective immune responses effectively blocking heterologous parasite entry to human cells.

KEYWORDS:

• In vitro culture
• malaria
• Plasmodium vivax
• protective immune response
• receptor-ligand interaction
• vaccine

Article Highlights

• Studying vaccine candidates in P. vivax has been limited by the parasite’s biology; no fully protection-inducing vaccine is thus available against the target species.

• The search for vaccine candidates has been based on antigenicity, comparing homology or specific genes’ low polymorphism. Despite this, an efficient methodology has not emerged for defining the appropriate molecules for inclusion in an effective vaccine.

• A functional approach based on identifying P. vivax merozoite-derived target cell binding regions should validate their importance for advancing studies in a suitable experimental model.

• A comprehensive approach is needed for perceiving suitable candidates to be included in developing a multi-epitope, multi-antigen vaccine which is completely effective against P. vivax.

Declaration of Interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The authors would like to thank the Universidad del Rosario for assuming publication charges.